he weeks of summer were slipping by. The first day of school was on the distant horizon and although the kids were blissfully ignorant, the parents knew there was one last major item of business to take care of before launching into full-on get-ready-for-school mode. Episode V was turning 5, and the kid needed a birthday party before the whole world disappeared into backpacks, class rosters, lunch boxes and new shoes.
Finally we had to acknowledge that we wouldn’t procrastinate any longer. A party needs guests, and that means invitations, and that means giving people some notice ahead of time. UnDorkMommy sat down at the computer to get the E-vite cranked up and asked Episode V “So what kind of birthday party do you want to have?”
The boy was lost in play at the moment, and could only offer 10% of his total mental bandwidth to the conversation. “I don’t know,” he replied.
“Do you want a superhero theme?” she asked.
“Mmmm” came the noncommittal response.
“What about a Lego theme?” The only answer from the boy was the sound he made of two plastic robots crashing into each other. “Or how about a bike party?” The sound of battling robots stopped as Episode V realized that UnDorkMommy was still talking to him.
“Um… what did you say?”
Just as UnDorkMommy was about to express her exasperation, DorkDaddy walked into the room. “I have an idea” he said with the wide-eyed smile that promised something epic and awesome was about to follow. “How about.. ((pause for dramatic effect)) a SUPER SCIENCE BIRTHDAY PARTY?!!?”
“YEAH! YEAH! YEAH!” shouted the boy.
DorkDaddy threw a smug wink to UnDorkMommy, which was returned by an icy sneer – at once a reminder of who’s who around the house and also a warning not to push his luck one millimeter further.
Later that night the division of labor was established. “You realize this one is all on you, right?” said UnDorkMommy.
“You handle the food and the invitations,” said DorkDaddy. “I’ll handle the entertainment.”
As usual, UnDorkMommy did a masterful job managing the logistics. There really was no question. As the day of the party approached, the only real unknown was whether or not UnDorkDaddy would be able to make good on his promise and deliver a “5th BIRTHDAY PARTY OF SCIENTIFIC AWESOMENESS!!”
Below is an account of how I ran things. Was I successful? I’ll let you be the judge.
E-vite invitations and reminders went out with specific instructions. This would be a parent-assisted birthday party. No drop-offs and pick-ups after the festivities. Kids were also encouraged to bring their bikes and helmets. The party would be held at the local park, and there would be some down time here and there, perfect for biking around the dirt track.
Between the kids Episode V knew and their siblings, we expected 18 children (and their parents). So we planned all activities for 20, just in case. Once everyone made it to the party it was time to gather around the table for the first experiment.
It’s important to point out that when teaching science, enthusiasm has to be high. The dork-factor has to be turned all the way up. Success in teaching science lives and dies in the presentation. The good news was that I am supremely qualified in both the scientific and the dork arenas. I made sure I brought my A-game.
I called all our little scientists over to the experimentation table where they found the scene pictured below. Each one of them had a pair of goggles (thank you Amazon.com) waiting for them. We took a moment to sharpie their names on their goggles and explain the rules: Nothing goes in your mouth. Everyone listens to instructions before starting. Etc, etc, etc. When they were sufficiently pumped-up, it was time to start the show.
Mentos and Diet Soda
mint flavored mentos candy, diet cola (diet seems to work best, but any carbonated cola will do) in a bottle (any size)… cans are too difficult to work with (and don’t hold enough soda to make a spectacle), a mop (because this gets incredibly messy).
The original, legendary experiment that, in one form or another, has spread like wildfire across YouTube, Facebook and the Twitterverse. It’s as simple as this: Get a bottle of diet cola. Carefully remove the cap so as not to release all the carbonation too quickly. Drop in three mint-flavored mentos, and stand back to watch the cola-geyser of awesomeness erupt in dramatic fashion – and make an incredible mess all over the place (I would strongly encourage you to file this experiment in the “outside only” category). If you’re really feeling spunky, do a YouTube search on “mentos and soda” to see all of the creative variations on a theme. For my money, when you’re wrangling 20 5-year-olds, simplicity is key.
Note: only the original mint-flavored mentos will work here. There are other flavor varieties, none of which work nearly as well for reasons I will explain later.
Another Note: Don’t throw away the soda bottles used in this experiment yet. Collect them all and have someone rinse them out thoroughly during the next experiment. You’ll use them again for the 3rd activity.
The reason why this works is a phenomena called “nucleation.” To explain let me change to a different but not unrelated topic. For water gas to condense into a droplet it turns out that the gas needs something to condense around… some slight irregularity in the environment to grab onto. Without that slight irregularity the gaseous water stays stuck in gaseous form. At extreme altitudes where airplanes fly, the air is so pure/clean that gaseous water, no matter how badly it may want to turn into water droplets (clouds), has nothing to grab onto (nucleate around). So the gaseous water up there stays gas until an airplane comes around. The plane’s engines leave exhaust and that exhaust is made up of itty-bitty particles. Those particles are just perfect for the gaseous water to nucleate around, condense from gas to liquid, and form itty-bitty water droplets. And that’s airplane contrails are formed.
The same goes for the carbon dioxide gas stored up in the soda. The carbon dioxide gas is actually dissolved in the liquid cola and desperately wants to get out by forming a gas bubble and escaping. The problem is the inner surface of the plastic soda bottle is so uniform, so smooth, the carbon dioxide has nothing to nucleate around to form a bubble. As it turns out, the surface of the mint-flavored mentos candy has the perfect texture for nucleation. Drop three candies in and there is more than enough surface area around the candies for all the carbon dioxide in the bottle to grab on to, form gaseous bubbles, and fizz out of the cola almost all at once. This is why the other flavored mentos don’t work nearly as well. They have a waxy coating to them which is almost as smooth as the inside of the cola bottle, and are therefore nowhere near as effective for nucleation.
Frame this experiment in the context of “states of matter,” which is to say solid, liquid and gas. The candy represents the solid, the soda the liquid, and the gas is the carbon dioxide dissolved in the cola. The question at hand is how to get the gas out of the liquid. For extra fun you can purchase commercially produced geyser tubes to make the reaction erupt higher and in more than one direction. It’s particularly fun to watch all the parents standing around at the party go running for cover when the fountain reaches more than 12’ high and the wind blows the cola into the crowd.
For a more merciful way to demonstrate solids, liquids and gasses a root beer float will do just as nicely. If you’re doing this activity in a classroom environment, it makes a nice way to wrap up a unit (and I can say from experience that root beer erupts just as effectively as diet cola).
At this point we sent the kids off to go race bikes around the track. While they were doing their thing we collected all the bottles together in a garbage bag. Coincidentally, Episode VI was starting to melt down so UnDorkMommy quick took him home to put him down for a nap (Grandma babysat), rinsed out all the soda bottles, and brought them back to the party before anyone was the wiser. While she was doing that, another dad and I wrapped up the entire mess, tablecloths and all, and stuffed it into another garbage bag for disposal. Like a well-oiled machine we gorilla taped two new tablecloths down, and set out the materials for the next experiment. We turned the entire thing around in 5 minutes and managed to avoid losing the attention of our little scientists. “Attention scientists! Find your goggles and your grownups and come on over for the next experiment!”
Experiment #2 was deliberately chosen for the #2 spot because it’s a little lower-key. You can’t keep kids at full RPM’s for the entire party, and I knew I wanted to finish with a bang. Best to bring it down a little.
colored plastic bowls, milk (the fattier the better), liquid detergent, plastic spoons, food coloring
Pour just enough milk to cover the bottom of the colored plastic bowl; about ¼” deep should be more than enough. Place a few drops of food coloring (5 or 6) at random spots on the surface of the milk, taking care not to stir the drops and blend them into the milk. Just leave ‘em sitting there. For best effect, use a number of different colors. Put a little liquid detergent into a spoon and drop by drop, one drop at a time, drip the detergent into the milk at varying distances from the food coloring drops. Watch as the detergent makes the food coloring drops dramatically swirl and blend in the milk like a bad 60’s acid trip. Observe one of your detergent drops close up and watch the food coloring churn in a tiny turbulent pattern.
Fats and oils (lipids) are very long, large molecules that are difficult to digest. In order to extract energy out of lipids our bodies first need to break them down into much smaller pieces – it needs to emulsify them. Just underneath our livers is the gallbladder which releases bile into our digestive system, the purpose of which is to emulsify the fats we eat so our bodies can better extract energy from lipids.
Where organic chemistry is concerned, detergents perform much the same as the bile in our digestive tracts. They break long lipid molecules down into much smaller chunks. When you put a drop of detergent into the milk, the detergent begins to emulsify the fats in the milk. The food coloring drops swirl, mix and churn because they follow the currents in the milk initiated by the emulsification.
If you want to get messy with things, you can hand each child at the party a potato chip and ask them to rub it between their hands until it’s smashed to oblivion (a little piece of hot dog would work too). Then have them reflect on what’s left on the palms of their hands. They should notice the grease right away. The grease is a lipid, and it’s in most foods that we eat. Since chewing grease doesn’t break it down, our bodies needs to find another way to emulsify it. That’s where the gall bladder and bile come into play.
A bottle of vinegar and oil salad dressing also makes an effective demonstration. Notice how the vinegar and oil is separated after it’s been sitting for a while. Shake the bottle vigorously and notice how the oil is now broken into many itty-bitty little droplets that are suspended in the vinegar. The lipids have been emulsified.
UnDorkMommy had carefully coordinated the delivery of the pizza to coincide with the Rainbow Milk experiment. By the time we were done everyone was getting hungry, and the pizza was piping hot and ready to go. I sent them over to the other tables to refill their tanks. Again, I took the opportunity to clean up from the previous experiment. We bundled everything up in the tablecloths, stuffed ’em in a garbage bag, and taped down fresh tablecloths like a Formula-1 pit crew. After everyone (except DorkDaddy) got a few slices of pizza in them, it was time to ramp-up the “Ooooh… Aaaaa” factor.
IMPORTANT NOTE: Although this activity is called “elephant toothpaste,” under no circumstances should any of the materials be put in the mouth. Adult supervision is a must.
a tablecloth, 6% hydrogen peroxide (the stuff you get at the pharmacy in the brown bottle is 3%… it’ll work, but it won’t be as dramatic. The 6% stuff comes from a hair salon), dish soap, food coloring, dry yeast, a soda bottle, cup, water, spoon
First things first: get a decent tablecloth down, preferably one with paper on one side and plastic on the other. This experiment is ultra-messy, so you’ll want the plastic side of the tablecloth down and the paper (absorbent) side up.
Place about three fingers (scotch reference) of 6% hydrogen peroxide into an empty soda bottle. If you’re recycling the bottles from the mentos/soda activity, be sure they’re thoroughly rinsed out. They don’t have to be dry. IMPORTANT NOTE: Hydrogen peroxide can irritate eyes and skin; concentrated hydrogen peroxide even more so. This part of the experiment should be done by grownups, and eye-protection is an absolute must. Into the bottle with peroxide, squirt a little bit of liquid dish soap and three or four (5 or 6) drops of the food coloring of your choice. Be careful not to shake up the solution and make it frothy. Just gently swirl the peroxide/soap/food coloring until it’s nice and uniform… minimal bubbles at this point.
Fill a separate cup about ½ full with water and stir in one spoonful of dry yeast (you can find dry yeast in the grocery store by the flour… took me a freakin’ hour to figure that out). When the yeast/water is well stirred, pour it into the bottle with the peroxide/soap/food coloring.
Stand back and watch an awesome, Technicolor, foamy mess bubble forth from your bottle. The reaction will keep going for a good long while, and very soon it will become clear why it’s called “elephant toothpaste”.
When the reaction is done it’s perfectly safe to touch. At this point it’s just soap and water. Notice that the foam is a little warmer than you would expect.
Hydrogen peroxide is a molecule with two hydrogens and two oxygens (H2O2). All by itself it wants to break down into water and oxygen gas (2H2O2→ 2H2O+O2). It’s the oxygen gas that you’re seeing when you see hydrogen peroxide bubble. The reaction is easily quickened if you introduce impurities (remember nucleation?) or even sunlight (that’s why it comes in brown bottles). The dry yeast acts as a nucleation site, which makes it easier for the hydrogen peroxide to break down. Tiny oxygen bubbles are then trapped in the dish soap, and the result is a really cool (and messy) foam that continues to froth out of the bottle like someone endlessly squeezing a tube of toothpaste.
It is an axiom in chemistry that whenever a bond is broken energy is released. That holds true for hydrogen peroxide breaking down into water and oxygen. The foam will feel slightly warm, like a plate fresh out of the dishwasher. Reactions like this are called “exothermic.” Had we used more concentrated hydrogen peroxide, more heat would have been released in the same space, and would therefore feel much warmer, even hot. In this regard, stick with the 6% peroxide. The reaction isn’t too exothermic, and isn’t too abrupt. It’s just right for a bunch of kids.
Do a “elephant toothpaste” search on YouTube and you’ll find all sorts of fantastic video variations on the same theme. If you’re doing this experiment in a classroom it makes a great way to wrap up the lesson.
3 experiments down. One to go. This time we sent the kids for cupcakes, and blowing out the candles. The pit crew did their thing again at the experiment tables. It was important to sugar the kids up because the next activity was the grand finale. By the time we were done we could hand ’em back to their parents for de-tox.
white Elmer’s glue, borax, two disposable cups, borax (or substitute liquid laundry detergent), water, food coloring, 2 plastic spoons, zip-lock baggie
Pour a healthy quantity of Elmer’s glue into a disposable cup (ideally about ½ full). Put in 3 or 4 (5 or 6) drops of the food coloring color of your choice and stir evenly with a plastic spoon.
In a separate cup fill about ½ full with water. With a separate, 2nd spoon scoop a spoonful of borax into the water and stir thoroughly. The borax won’t dissolve particularly well in water, but enough will get in solution to do the trick.
NOTE: Boron is toxic via ingestion. As always, nothing used in this experiment should wind up in anyone’s mouth. Adult supervision please.
At this point I should point out that the entire borax/water step can be substituted with straight-up liquid laundry detergent. It certainly simplifies the entire procedure with fewer steps, and for that reason that’s the way we went at the party (with 18 kids to wrangle, simplicity is key). But having done the experiment both ways I have to say, the results are much better with borax. The borax gak is more rubbery, where the detergent gak is more whispy, runny, sticky and slimy. If you don’t want the stuff getting in your kid’s hair, on their clothes and all over the car upholstery, rubbery is better. In any case, be sure to have a zip-lock baggie handy for storage when you’re all done. Gak preserves pretty well in a zip-lock.
Before the powdered borax in water settles to the bottom of the cup, pour a healthy quantity of water/borax into the cup with the colored glue and stir vigorously. Stirring will require a little strength as the reaction takes place and the concoction begins to gel. At some point it may require an adult with a stronger arm. Additionally, the mixture tends to form “glue bubbles” where a thin skin of rubbery slime encapsulates a wet, sticky bubble of unreacted glue. At some point the scientist will have to scoop the concoction out of the cup with his/her hands (don’t worry, everything here is safe to touch) and kneed it around to incorporate as much borax solution as possible.
Eventually the scientist will be holding in his/her hands an awesome, slimy, nasty handful of colored gak. If the results seem too sticky, too liquid for your tastes, just add more borax solution to firm it up to the desired consistency. Eventually it shouldn’t stick to your scientist’s hands.
This is a fantastic lesson in polymerization. In chemistry, a fancy word for a plastic is a “polymer.” A polymer is a fancy name for a long chained-molecule where the links in the chain are the same identical units repeating over and over. If the long chain is called a polymer, an individual link is called a “monomer.”
As far as this experiment goes, Elmer’s glue is a chemical called polyvinyl acetate. By itself the polyvinyl acetate (glue) is a runny liquid (the “polyvinyl” parts are really long chains by themselves and tend to get tangled, so glue isn’t as runny as other liquids… but it’s a liquid none the less). The boron in borax likes to reach out and make four bonds with two different polyvinyl chains (we call that new structure a cross-linked polymer)
It isn’t polyvinyl acetate, it’s polyvinyl alcohol. But you get the point.
essentially linking them all up together and making the big long polyvinyl molecules even more likely to get tangled — which in turn changes the solution from a thickish liquid to a stable gel.
When discussing polymers and monomers, first pull out a bunch of same-sized legos (duplo blocks work even better because they’re bigger and easier to see). Explain how, on their own, each lego brick is a monomer. Under the proper conditions it’s possible to link them all up into a big, long chain. In chemistry, that chain is called a polymer… made up of individual, identical monomers.
Next get the kids up off their butts and out into a defined, open space. Instruct them to wander around on their own, herd-style, within the space. Notice how easy it is to move around, even if they do bump into another kid once in a while. Then, when you shout “CATALYST” each kid needs to find the kid closest to them and link arms, a different kid on each arm, eventually making a long (polymer) chain of linked (monomer) kids. Now instruct the chain to wander around in the same defined space without breaking the links. They’ll quickly see it’s a lot tougher to wander. That’s why the glue goes from liquid to gel after the polymerization reaction.
And THAT, ladies and gentlemen, is how to throw a 5th birthday party of scientific awesomeness!!
What do you think?